Influence of the Chelation Process on the Stability of Organic Trace Mineral Supplements Used in Animal Nutrition

SIMPLE SUMMARY: Organic trace minerals (OTMs) are recognised globally as being a more bioavailable source of mineral than their inorganic counterparts. Whilst there are many forms of mineral products available for use in animal nutrition, these have unfortunately been generically entitled “organic trace minerals” by virtue of the fact that the trace elements in question are complexed or otherwise associated with organic molecules. The process of chelating transition elements such as copper, iron or zinc, for instance, typically involves reacting inorganic mineral salts with suitable bonding groups, such as a peptides or amino acids, during which the mineral becomes part of a biologically stable structure. Numerous production processes have been developed, ranging from highly specific and controlled reaction processes to more involved chemical synthesis routes. The production process used determines the product’s efficacy. Given the vastly different products that exist in the marketplace, the importance of understanding the physical and chemical differences between them cannot be overstated, and as such, manufacturing processes that affect the pH stability and functionality of the finished products were assessed in this work. The results showed that in the case of proteinate type products, the hydrolysis procedure used to generate the chelating peptides had a significant impact on proteinate pH stability, a key determinant of the product’s performance in the animal. ABSTRACT: The effect of the chelation process on the pH-dependent stability of organic trace minerals (OTMs) used as mineral supplements in animal nutrition was assessed using analytical techniques such as potentiometry, Fourier Transform Infrared Spectroscopy (FTIRS) and amino acid profiling. The aim was to understand the influence and relative importance of the manufacturing conditions on mineral chelation and the subsequent pH stability of OTMs. A selection of OTMs were assessed over a wide pH range to account for the typical environmental changes encountered in the gastrointestinal (GI) tract. In the case of proteinate type products, the potentiometric assessment of free mineral concentration indicated that the hydrolysis procedure used to generate the chelating peptides was the major influencer of the pH stability of the products. Many products are available under the umbrella term “OTMs”, including amino acid complexes, amino acid chelates, polysaccharide complexes and proteinates. Significant differences in the pH-dependent stability of a range of commercially available OTMs were observed.